drm/i915/gt: Remove presumption of RCS0

We now track features correctly instead of probing i915->engine[RCS0]
which is much more flexible and avoids any nasty surprises.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190705124325.14270-2-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/intel_engine_cs.c

@@ -448,12 +448,6 @@ int intel_engines_init_mmio(struct drm_i915_private *i915)
 	if (WARN_ON(mask != engine_mask))
 		device_info->engine_mask = mask;
 
-	/* We always presume we have at least RCS available for later probing */
-	if (WARN_ON(!HAS_ENGINE(i915, RCS0))) {
-		err = -ENODEV;
-		goto cleanup;
-	}
-
 	RUNTIME_INFO(i915)->num_engines = hweight32(mask);
 
 	intel_gt_check_and_clear_faults(&i915->gt);